With the development of data storage techniques, various data storage devices now provide users with higher and higher data storage capacity, and also their speed of accessing data has been increased greatly. Besides the increase of data storage capacity, users also impose greater and greater demands on data reliability and response time of storage systems. So far various RAID-based data storage systems have been developed to increase data reliability. When one or more disks in a storage system fail, data in failed disks can be recovered from data in other disks operating normally.
The storage system may be accessed via storage control nodes. In a typical active-active type of storage system, two storage control nodes work jointly to process data access operations on the storage system and further provide higher usability and better performance. Each storage control node has its own memory (e.g. cache), and memories in two storage control nodes operate in a mirrored style. The two storage control nodes may receive in parallel data access instructions from the outside, so such a problem might arise that the two storage control nodes concurrently perform operations to the same storage area. At this point, it becomes a focus of research regarding how to provide a secure and reliable locking mechanism to avoid conflicts between operations of the two storage control nodes.